1. Field of Invention
The present invention relates to the technical field of nucleic acid-based detection, and more particularly to a nucleic acid aptamer probe and use thereof in tumor detection.
2. Description of Related Arts
A tumor is a common disease threatening the health of a human body. An accurate immunophenotyping of tumor cells is advantageous in implementing an early diagnosis and therapy of the tumor cells, so that the cure rate of tumor is increased. Antigen-antibody reaction is the basis of immunodiagnosis. The rapid development of antibody technology in past years has made great contributions to tumor therapy and diagnosis research. However, the antibody technology has encountered unprecedented challenges since the appearance of nucleic acid aptamers.
Nucleic acid aptamers are synthetic oligodeoxynucleotides designed according to rigorous recognition and binding affinities between nucleotides, and are obtained by screening through systematic evolution of ligands by exponential enrichments (SELEX). Nucleic acid aptamers not only have features similar to antibodies, such as highly specific recognition and highly binding affinities to targets, but are also advantageous in many aspects. Such advantages include: a small molecular weight, non-immunogenicity, variety of targets (including enzyme, growth factor, antigen, gene regulator, cell adhesion molecule, complete tumor cell, and etc.), a simple synthesis process, good repeatability, flexible modification, convenient long period storage, and transport at normal temperature etc. These characteristics make the nucleic acid aptamers to be acknowledged and accepted as tumor diagnosis probes; tumor recognition and detection methods based on nucleic acid aptamers have gradually become a novel, widespread, and applicable technology which brings in a new spring for the development in the field of typing, diagnosis, and therapy of tumor cells.
In the disclosure of “Aptamers Evolved from Live Cells as Effective Molecular Probes for Cancer Study.” Proc Nati Acad Sci USA 2006, 103 (32): 11838-11843; Dihua Shangguan, YingLi, ZhiwenTang, et al., a cell-SELEX strategy against whole living cells is disclosed. In this strategy a group of specific nucleic acid aptamers has been generated for the specific recognition of leukemia cells, and nucleic acid aptamers with fluorescence dye labelings are successfully used for effective recognition and detection of target leukemia cells mixed with normal human bone marrow aspirates. The research group further employs the cell-SELEX strategy to generate a series of nucleic acid aptamers for the specific recognition of tumor cells corresponding to lymphoma, liver cancer, lung cancer, and etc. These nucleic acid aptamers have been widely used for typing and detecting a variety of tumor cells or tissues. However, the current tumor detection method based on nucleic acid aptamers still mainly uses a single signal labeling means, such as fluorescent or radioactive labeling, in which the nucleic acid aptamers serve as target molecules and identify tumor cells through the binding affinity difference between the nucleic acid aptamers and the target and non-target cells. Since an inevitable non-specific adsorption exists between the nucleic acid aptamers and the non-target cells, this method cannot meet the requirement of a convenient, fast, highly specific and highly sensitive analysis of a complex mixture and thus implementation of an early diagnosis and development of a related therapy of the tumor in a clinical detection is limited.